An Coimisiún Pleanála, the new name for the planning appeals board, has relaxed the restrictions placed on the utilisation of the new north runway at Dublin airport and its change of heart has been welcomed by the chief executive of the Dublin Airport Authority, Kenny Jacobs. The announcement was also welcomed, but with less enthusiasm, by the two principal customers at the airport, Aer Lingus and Ryanair.

The tangled history of this project dates back to the 1980s, when Dublin had two intersecting runways – both limited in length and unsuitable for the composition of traffic.

Transatlantic flights were forced to land at Shannon under an Irish Government regulation designed to appease regional interests in the mid-west, and it took on the bulk of its fuel load at Shannon. This restriction was contested at the time, as Aer Lingus was keen to develop its North American business and reality eventually intruded, ending the ‘compulsory Shannon stopover’ as it was called.

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Travellers disliked the delays at Shannon and many Dublin-origin fliers had chosen to backtrack, connecting first to London’s Heathrow and from there direct to numerous destinations in the US and Canada. A trip from Dublin to many a North American city with direct service from Heathrow was quicker than the Aer Lingus service from Dublin via Shannon, which for most destinations meant a further transfer at a US airport. Not surprisingly, Aer Lingus had a small transatlantic business and no transfer traffic from the UK or continental Europe was attracted to Dublin.

Expansion

The airport built a new and longer east-west runway called 10-28 in 1985, with capacity to accommodate all of the traffic expected. This made direct non-stop service to North America feasible for Aer Lingus, but it had to wait until 2005 for the Shannon detour to be discontinued by the Irish Government.

The airport also acquired land to the north at modest cost, knowing that twin parallel runways, one for take-offs and one for landings, would eventually be needed. So it proved and after several deferrals due to interruptions in traffic growth, the new north runway was completed in 2022, on time and on budget, only to be caught up in yet another planning controversy.

This was a rare example of long-term planning by a State agency and the new north runway, well-flagged in advance, cost €325m, not merely on budget but one of the least costly major runways delivered at a European airport in recent decades. An Bord Pleanála was responsible for imposing a capacity of 32 million passengers per annum at Dublin airport as part of the planning conditions for terminals 1 and 2.

Layout

One of the advantages of the twin-parallel layout preferred in larger airports is that utilisation is maximised where one is devoted to take-offs and one to landings. Dublin airport is busy with take-offs in the early morning as the home-based fleets of Aer Lingus and Ryanair get away.

There were 77 take-offs last Saturday before 8am, the first at 5.30am, and numerous arrivals after midnight – airlines do not earn money from parked aircraft. There were also 17 long-haul arrivals before 8am, the first from New York at 4.25am. The prevailing winds often drive aircraft across the Atlantic ahead of schedule, so the first arrivals can turn up even earlier and the short-haul arrivals also commence before 8am.

So the airport is busy with arrivals and departures very early in the morning. Unless the second runway is available to separate arrivals and departures, the capacity to allocate slots is impaired. The night flying restrictions, which were imposed, would have prevented Dublin airport, where slots are already scarce, from solving the problem by building the second runway as it had planned 40 years ago. This it had done at low cost, only to discover that the local council has its own ideas about running large airports.

Future

Aer Lingus was acquired by International Airlines Group (IAG), owners of British Airways and Iberia, in 2015 with a view to exploiting Dublin’s potential as an east-west transfer point, given the constraints at Heathrow. Airports on Europe’s edge, like Helsinki, Lisbon and Istanbul, can cut down on back-tracking through the hubs in Europe’s more central locations and thus help mitigate aviation’s carbon emissions. Adequate runway capacity means that short-haul connecting flights can be bunched into waves to facilitate long-haul connections, but only where slot allocations are flexible.

This is now possible at Dublin, where total available slots could be doubled, or close to it. A generous compensation scheme for the small number of home-owners in the vicinity has long been available.

*This article has been amended on 28 July 2025.